Telephony application server charging for evolved packet system fallback

ABSTRACT

A server of a fifth generation (5G) network can provide substantially real-time charges for a UE during fallback to another network. A Telephony Application Server (TAS) in an IP Multimedia Subsystem (IMS) can identify Evolved Packet System Fallback (EPSFB) and report the EPSFB to a charging system to cause the charging system to generate accurate charges for user equipment communicating over the 5G network and the other network. The TAS can comprise logic to identify a change in P-Access-Network-Information associated with each network, and generate a call detail records for billing, or real-time communication via an online charging and/or offline charging for the served UE. Information (a user profile, call detail records, instance of EPSFB, etc.) associated with the TAS can be used to make network improvements that decrease instances of EPSFB and increase an amount of new radio services available to UEs.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 17/370,532, filed Jul. 8, 2021, titled “TELEPHONYAPPLICATION SERVER CHARGING FOR EVOLVED PACKET SYSTEM FALLBACK,” theentirety of which is incorporated herein by reference.

BACKGROUND

Modern terrestrial telecommunication systems include heterogeneousmixtures of second, third, and fourth generation (2G, 3G, and 4G)cellular-wireless access technologies, which can be cross-compatible andcan operate collectively to provide data communication services. GlobalSystems for Mobile (GSM) is an example of 2G telecommunicationstechnologies; Universal Mobile Telecommunications System (UMTS) is anexample of 3G telecommunications technologies; and Long Term Evolution(LTE), including LTE Advanced, and Evolved High-Speed Packet Access(HSPA+) are examples of 4G telecommunications technologies.Telecommunications systems may include fifth generation (5G)cellular-wireless access technologies to provide improved bandwidth anddecreased response times to a multitude of devices that may be connectedto a network.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is set forth with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical items or features.

FIG. 1 depicts an example network environment in which an example userequipment can connect to a telecommunication network to implement thetechniques described herein.

FIG. 2 depicts an example system architecture for a fifth generation(5G) telecommunication network.

FIG. 3 depicts an example Telephony Application Server (TAS)implementing techniques to cause the determination of charges duringEvolved Packet System Fallback (EPSFB) for an example user equipment(UE).

FIG. 4 depicts an example Telephony Application Server (TAS)implementing techniques to cause the determination of online chargesduring Evolved Packet System Fallback (EPSFB) for an example userequipment (UE) associated with a pre-paid account.

FIG. 5 depicts a flowchart of an example process for determining chargesby an example server for an example user equipment.

FIG. 6 depicts another flowchart of an example process for determiningcharges by an example server for an example user equipment.

FIG. 7 depicts an example system architecture for a user equipment.

DETAILED DESCRIPTION

As devices compete for available bandwidth to receive Voice over NewRadio (VoNR) and other services over a fifth generation (5G) network,fallback to one or more other networks may occur. This applicationdescribes techniques for determining charges during Evolved PacketSystem Fallback (EPSFB) over a 5G network. For example, charge detailrecords (CDR) are established by a telephony application server (TAS)based on an identifier associated with a user equipment (UE) thatindicates a type of technology associated with a communication request.In some examples, the TAS can facilitate determinations of real-timecharges for services provided by New Radio (NR), Long Term Evolution(LTE), and so on during EPSFB by tracking changes inP-Access-Network-Information (PANI) associated with the UE. In this way,the TAS can determine real-time changes in technology type to initiateor access charges for each portion of a communication over varioustechnology types. In some examples, the TAS can identify a change intechnology type (e.g., 5G, LTE, etc.) and communicate the changes to acharging system that determines charges using logic that accounts foreach change during the communication. In addition to improving accuracyof charges during fallback, the TAS can also output records usable toidentify areas of the 5G network that can be improved to reduce fallbackfor future communications.

In various examples, the TAS can comprise logic to identify a change inP-Access-Network-Information associated with each network and generatecall detail records for usable to determine an online charge and/or anoffline charge for the UE. Using the techniques described herein, theTAS can initiate, establish, maintain, manage, or otherwise determinechanges in technology that can be communicated to a charging system thatdetermines online charges and/or offline charges for a communicationoriginating with a first UE to a second UE. In some examples, thecharges may be associated with call detail records, an offline charge,and/or an online charge. By way of example and not limitation, the TAScan facilitate the determination of charge(s) for a Voice over New Radio(VoNR), a Video over New Radio (ViNR), a Voice over LTE (VoLTE), and/ora Video over LTE (ViLTE), just to name a few. In such examples, the TAScan cause the charging system to implement rating logic that accuratelydetermines charges for portions of a communication (e.g., a text, voice,video, and/or other call) occurring over different types of networktechnologies.

In some examples, the TAS can receive a message from a first UEindicating a request for a VoNR communication with a second UE andidentify that EPSFB requires the communication to fallback to anothernetwork, such as a fourth generation network. The TAS can, for example,determine a change in identifiers associated with the networks such asby accessing P-Access-Network-Information (PANI) that identifies a typeof technology used by each network. In some examples, the PANI canidentify an access-type and technology in a SIP header. The TAS may alsoor instead access or determine other types of SIP headers such as a SIPUser-Agent header that identifies device type information about the UE.In various examples, the TAS can determine changes in technology andcommunicate the changes to various components, servers, and/or systemsresponsible for determining charges in substantially real-time includingwhen the UE originating the communication is associated with a pre-paiddevice. Additional details for the TAS determining changes in technologythat leads to determining appropriate charges can be found elsewhereincluding in FIG. 1 .

The charging techniques described herein can enable a UE (e.g., anoriginating and/or a terminating device) to be charged for portions of acommunication according to an amount of time that the communication usesdifferent networks. That is, a message requesting a VoNR communicationmay instead be completed or communicated at least in part on an LTEnetwork, and charges can be determined for a communication over the LTEnetwork rather than for the VoNR communication indicated by the messagerequest. Further, a pre-paid device without sufficient credit tocomplete a call using a VoNR communication can still be completed asanother type of communication (e.g., VoLTE) during EPSFB by anothernetwork using the techniques described herein (as opposed to beingdenied service on the 5G network that is otherwise unable to initiatethe VoNR communication due to limited bandwidth, insufficient credit,etc.). Based at least in part on the TAS detecting a change intechnology, the TAS can generate data indicating the changes intechnology (along with a period of time associated with each technologyin some examples) for communication to a charging system that candetermine charges based on logic that identifies a period of time that acommunication uses a particular network, including when thecommunication uses or otherwise returns to the 5G network to provide theVoNR communication.

In some examples, the TAS can provide information to another server orcomponent of the 5G network indicating which area(s) of the 5G networkexperiences EPSFB to enable an improvement of the 5G network. Forexample, one or more call detail records output by the TAS can be used(by the TAS or other server) to generate information that identifies thearea(s) of the network having instances of fallback. In such examples,the information can be sent to another component, machine learned model,and/or server of the 5G network that is configured to determine networkparameters that maximize throughput of UEs in the corresponding area(s).In this way, the TAS can be used to provide visibility of fallbackoccurrences to mitigate the network settings, configurations, and thelike and/or to identify where additional equipment can be deployed toimprove the 5G network.

The systems and techniques disclosed herein may provide for processingan identifier associated with a UE to generate charges when initiating,maintaining, and terminating a communication with another UE, includingduring fallback to a network other than a 5G network. In some examples,the TAS may be part of an Internet Protocol (IP) Multimedia Subsystem(IMS) or other system in the 5G network. Further description ofproviding charging techniques by the TAS can be found throughout thisdisclosure including in the figures below.

FIG. 1 depicts an example network environment 100 in which an exampleuser equipment (UE) can connect to a telecommunication network to engagein communication sessions for voice calls, video calls, messaging, datatransfers, or other types of communications. For example, the UE 102 canconnect to a 5G system 104 for sending a communication (e.g., a VoNRcommunication, a ViNR communication, etc.) to one or more additional UEs(e.g., UE 106).

As depicted in FIG. 1 , the 5G system 104 comprises a 5G core network108 and an IP Multimedia Subsystem (IMS) 110 (e.g., an IMS core network)that receives a message 112 from the UE 102. The IMS 110 is showncomprising a TAS 114 that is configured to identify, generate,communicate, or otherwise determine a change in technology usable by acharging system to determine charge(s) for the UE 102 to communicatewith the UE 106. In some examples, the UE 102 can generate the message112 that includes a connection request to establish a voice, text,and/or video call with the UE 106. In such examples, the UE 102 can beassociated with an account on the 5G network 108, a pre-paid device, ora mobile virtual network operator (MVNO), just to name a few. Themessage 112 (or a portion thereof) can be sent over the 5G core network108 for processing by a telephony application server (TAS) 114 (or otherapplication server configured to process voice, text, and/or video callssuch as an internet protocol short message gateway (IPSM-GW), etc.)which can perform functionality as described herein including accessing,receiving, or identifying an identifier (e.g., a PANI) associated withthe UE 102 to determine charge(s) for communicating with the UE 106 as acommunication session over a unique channel.

In various examples, the 5G system 104 can initiate, establish,maintain, format, augment, manage, or otherwise determine secureexchange of text, video, and/or photos including determining whether theUE 102 undergoes fallback (e.g., EPSFB) to communicate with the UE 106.As depicted in FIG. 1 , the TAS 114 comprises a charge interface 116 andan identifier interface 118, and the 5G system 104 further comprises anintegrated marketing communication (IMC) 120, an online charging system(OCS) 122, enterprise mobility management (EMM) 124, and/or a charginggateway (CG) 126 (also referred to as a charging gateway function(CGF)). In various examples, the techniques described herein can includethe 5G system 104 implementing one or more of the charge interface 116,the identifier interface 118, the IMC 120, the OCS 122, the EMM 124,and/or the charging gateway 126 to determine charge(s) for the UE 102and/or the UE 106. In various examples, the OCS 122 and the CG 126 maybe a system separate from the 5G system 104 that is configured tocommunicate with the IMS 110 to exchange data (e.g., technology changedata, charge data, etc.) over a network to implement the techniquesdescribed herein. In addition of in the alternative, the IMS 110 may bea system separate from the 5G system 104 and be configured tocommunicate with the 5G system 104, the 5G core network 108, the 4Gsystem 130, and/or the 4G core network 132.

To implement the techniques described herein, in various examples the 5Gsystem 104 and/or the IMS 110 can include one or more of: an a proxycall session control function (PCSCF), an interrogating call sessioncontrol function (ICSCF), a serving call session control function(SCSCF), a serving gateway (SGW), a packet data network gateway (PGW), apolicy and charging rules function (PCRF), and an internet protocolshort message gateway (IPSM-GW), a short message service center (SMSC),and an evolved packet data gateway (ePDG) 328, and a Home SubscriberServer (HSS), just to name a few. In addition, the techniques describedherein may be implemented using Real-Time Protocol (RTP) and/orReal-Time Control Protocol (RTCP), among others.

As mentioned, the 5G system 104 can process the message 112 and providecommunication to the UE 106 during EPSFB 128 in which a 4G system (LTE)130 employs a 4G core network 132 to communicate a fallback message 134to the UE 106. Additionally or alternatively, the 5G system 104 canprocess the message 112 and provide (e.g., initiate, establish, and/ormaintain) the communication associated with the message 112 to the UE106 as a 5G message 136. In some examples, a communication sessionbetween the UE 102 and the UE 106 can include one or more instances ofthe fallback message 134 and the 5G message 136, and the IMS 110 (viathe TAS 114) can generate data indicating the one or more instance offallback, and communicate the data to a charging system such as the OCS122 and/or the CG 126 to determine charges for each instance associatedwith each message type (e.g., charge(s) for the 5G message(s) on the 5Gcore network 108 and charge(s) for the fallback message(s) on the 4Gcore network 132).

The UE 102 and the UE 106 represent any device that can wirelesslyconnect to the telecommunication network, and in some examples mayinclude a mobile phone such as a smart phone or other cellular phone, apersonal digital assistant (PDA), a personal computer (PC) such as alaptop, desktop, or workstation, a media player, a tablet, a gamingdevice, a smart watch, a hotspot, or any other type of computing orcommunication device. An example architecture for the UE 102 and UE 106is illustrated in greater detail in FIG. 7 .

In various examples, the 5G system 104 can represent functionality toprovide communications between the UE 102 and the UE 106, and caninclude one or more radio access networks (RANs), as well as one or morecore networks linked to the RANs. For instance, a UE 102 can wirelesslyconnect to a base station or other access point of a RAN, and in turn beconnected to the 5G core network 108. The RANs and/or core networks canbe compatible with one or more radio access technologies, wirelessaccess technologies, protocols, and/or standards. For example, wirelessand radio access technologies can include fifth generation (5G)technology, Long Term Evolution (LTE)/LTE Advanced technology, otherfourth generation (4G) technology, third generation (3G) technology,High-Speed Data Packet Access (HSDPA)/Evolved High-Speed Packet Access(HSPA+) technology, Universal Mobile Telecommunications System (UMTS)technology, Global System for Mobile Communications (GSM) technology,WiFi technology, and/or any other previous or future generation of radioaccess technology. In this way, the 5G system 104 is compatible tooperate with other radio technologies including those of other serviceproviders. Accordingly, the message 112 from the UE 102 may originatewith another service provider (e.g., a third-party) and be processed bythe TAS 114 independent of the technolog(ies) or core network associatedwith the service provider.

Generally, the charge interface 116 provides functionality to generatedata indicating a change in technology, technologies used forcommunication, and/or call detail record(s) (CDR) that may be associatedwith one or more charges corresponding to online charges and offlinecharges associated with the communication (e.g., the message 112, thefallback message 134, and/or the 5G message 136) between the UE 102 andthe UE 106. For instance, the charge interface 116 can generate a CDRthat includes an amount of time the communication is associated witheach technology type. In some examples, the OCS 122 and/or the CG 126can determine charges based at least in part on the CDR(s) byimplementing one or more diameter based interfaces such as an onlinecharging (Ro) interface (not shown) and/or an offline charging (Rf)interface (not shown) that implement various policies and controls todetermine charges for respective network types used during thecommunication. In various examples, the OCS 122 and/or the CG 126 (orother mediation system) can include logic to combine and/or generatecharges from the one or more network types.

The identifier interface 118 can, in some examples, providesfunctionality to access, receive, store, or otherwise determine anidentifier associated with one or more UEs (e.g., the UE 102 and/or theUE 106). In some examples, the identifier interface 118 can identifyP-Access-Network-Information (PANI) (or other SIP header(s)) thatidentifies a technology type used by the UE 102 in association with themessage 112, the fallback message 134, and/or the 5G message 136. Inthis way, the identifier interface 118 can determine that the message112 is associated with a first PANI that identifies the technology typeas the 5G system 104 and that the fallback message 134 is associatedwith a second PANI that identifies the technology type as the 4G system130. In such examples, the identifier interface 118 can store the firstPANI, and determine, based on comparing the first PANI and the secondPANI, that a change in PANI has occurred (e.g., due to EPSFB 128). Insuch examples, the charge interface 116 can initiate a charge for eachmessage type based at least in part on the comparison of the first PANIand the second PANI by the identifier interface 118.

As mentioned, the TAS 114 can employ or otherwise be associated with oneor more of: the IMC 120, the OCS 122, the EMM 124, and/or the CG 126 todetermine charge(s) for the UE 102. For instance, the IMC 120 canprovide functionality to enable, because of the EPSFB 128 to the 4Gsystem 130, the OCS 122 to determine online charging for instance whenthe UE 102 is associated with a pre-paid device and/or an MVNO. The EMM124 and/or the charging gateway 126 can, for example, manage and/orstore data associated with the communication (e.g., CDR file(s)) usableto determine charges (e.g., by parsing the CDR file(s)) such as aduration of the call, a type of technology used, a type of network used,and so on. Addition discussion of the IMC 120, the OCS 122, and/or theCG 126 can be found throughout this disclosure including in FIGS. 3 and4 .

In some examples, the 5G core network 108 can represent a service-basedarchitecture that includes multiple types of network functions thatprocess control plane data and/or user plane data to implement servicesfor the UE 102. In some examples, the services comprise richcommunication services (RCS), a VoNR service, a ViNR service, and thelike which may include a text, a data file transfer, an image, a video,or a combination thereof. The network functions of the 5G core network108 can include an Access and Mobility Management Function (AMF), aSession Management Function (SMF), a User Plane Function (UPF), a PolicyControl Function (PCF), and/or other network functions implemented insoftware and/or hardware, just to name a few. Examples of networkfunctions are also discussed in relation to FIG. 2 , and elsewhere.

FIG. 2 depicts an example system architecture for a fifth generation(5G) telecommunication network. In some examples, the telecommunicationnetwork can comprise the 5G core network 108 in FIG. 1 that includes aservice-based system architecture in which different types of networkfunctions (NFs) 202 operate alone and/or together to implement services.Standards for 5G communications define many types of NFs 202 that can bepresent in 5G telecommunication networks (e.g., the 5G core network108), including but not limited to an Authentication Server Function(AUSF), Access and Mobility Management Function (AMF), Data Network(DN), Unstructured Data Storage Function (UDSF), Network ExposureFunction (NEF), Network Repository Function (NRF), Network SliceSelection Function (NSSF), Policy Control Function (PCF), SessionManagement Function (SMF), Unified Data Management (UDM), Unified DataRepository (UDR), User Plane Function (UPF), Application Function (AF),User Equipment (UE), (Radio) Access Network ((R)AN), 5G-EquipmentIdentity Register (5G-EIR), Network Data Analytics Function (NWDAF),Charging Function (CHF), Service Communication Proxy (SCP), SecurityEdge Protection Proxy (SEPP), Non-3GPP InterWorking Function (N3IWF),Trusted Non-3GPP Gateway Function (TNGF), and Wireline Access GatewayFunction (W-AGF), many of which are shown in the example systemarchitecture of FIG. 2 .

One or more of the NFs 202 of the 5G network 108 can be implemented asnetwork applications that execute within containers (not shown). 5G NFs202 can execute as hardware elements, software elements, and/orcombinations of the two within telecommunication network(s), andaccordingly many types of 5G NFs 202 can be implemented as softwareand/or as virtualized functions that execute on cloud servers or othercomputing devices. Network applications that can execute withincontainers can also include any other type of network function,application, entity, module, element, or node.

The 5G core network 108 can, in some examples, determine a connectionbetween an Internet Protocol (IP) Multimedia Subsystem (IMS) thatmanages a communication session for the UE 102, including sessions forshort messaging, voice calls, video calls, and/or other types ofcommunications. For example, the UE 102 and the IMS 110 can exchangeSession Initiation Protocol (SIP) messages to set up and manageindividual communication sessions. In some examples, the IMS 110 cangenerate a CDR to indicate changes in an identifier (e.g., a PANI)between NR, LTE, and/or Universal Mobile Telecommunications System(UMTS).

FIG. 3 depicts an example Telephony Application Server (e.g., the TAS114) determining changes in technology usable for generating chargesduring Evolved Packet System Fallback (e.g., the EPSFB 128) for anexample user equipment (e.g., the UE 102 and/or the UE 106). Forexample, the UE 102 may send the message 112 to the 5G core network 108which can cause the fallback message 134 to be sent to the UE 106.Though the TAS 114, the IMC 120, and the CG 126 are illustrated in FIG.3 individually, it is understood that the TAS 114, the IMC 120, and/orthe CG 126 (of functionality provided therefrom) may be directly coupledto and/or integrated into the IMS 110 or other sub-system of the 5Gsystem 104. However, in other examples functionality provided by the TAS114 may be implemented as a system separate from the IMS 110 (e.g., toprovide services to other network architectures and/or other networkoperators).

In some examples, a messaging flow as shown in FIG. 3 can representactivity to determine conditions by the TAS 114 during the establishingand maintaining of a communication (e.g., the message 112, the fallbackmessage 134, and/or the 5G message 136) between the UE 102 and the UE106. The TAS 114 can generate data representing the conditions forsending to a charging system, such as the charging gateway 126. Forexample, a UE 102 can send an INVITE(NR) message to the IMS 110 toinitiate a call to the UE 106. The IMS 110 can forward the INVITE(NR)message to the TAS 114. In some examples, the UE 102 can send aprovisional response acknowledgement PRACK(NR) message to the IMS 110which can forward the PRACK(NR) to the TAS 114. As illustrated in FIG. 3, the UE 102 can undergo EPSFB (e.g., EPSFB 128) and send anacknowledgement ACK(LTE) to the IMS 110 which can forward the ACK(LTE)to the TAS 114 to indicate a change of network. In various example, themessage sent to the TAS 114 can include an identifier indicating atechnology type of the network, such as a PANI associated with the 5Gnetwork and a PANI associated with the LTE network.

In some examples, the UE 102 can communicate with the UE 106 over the 5Gnetwork and/or the 4G network, and the TAS 114 can cause thedetermination of charge(s) for the UE 102 during the communication inreal-time. After the call ends, the TAS 114 can exchange chargeinformation (e.g., shown as charge push/pull in FIG. 3 ) about the oneor more charges with the CG 126. The TAS 114 and/or the CG 126 candetermine call detail records based at least in part on logic (e.g., amathematical algorithm, a machine learned algorithm, and the like) thatcombines or aggregates the charges. In such examples, the TAS 114 canact as an originating TAS by receiving an invite from the UE 102.

FIG. 3 also depicts the TAS 114 acting as a terminating TAS (e.g.,facilitating termination of the UE 106 to another component or UE). Forinstance, the UE 106 can send a session progress 183(NR) message to theUE 102 which causes the 183(NR) message to be sent from the IMS 110 tothe TAS 114. As illustrated in FIG. 3 , the UE 106 can undergo EPSFB(e.g., EPSFB 128) and send an invite 200OK INV(LTE) to the UE 102 whichcauses the IMS 110 to forward the 200OK INV(LTE) to the TAS 114 toindicate a change of network (e.g., a change in PANI indicating that theUE 106 has joined an LTE network as a result of the UE 106 experiencingfallback). After the call ends between the UE 106 and the UE 102, theTAS 114 can exchange charge information (e.g., shown as charge push/pullin FIG. 3 ) about the one or more charges with the CG 126.

FIG. 4 depicts an example Telephony Application Server (e.g., the TAS114) determining changes in technology usable for generating onlinecharges during Evolved Packet System Fallback (EPSFB) (e.g., the EPSFB128) for an example user equipment (e.g., the UE 102 and/or the UE 106)associated with a pre-paid account. For example, the UE 102 may send themessage 112 to the 5G core network 108 which can cause the fallbackmessage 134 to be sent to the UE 106. In other examples, the UE 106 cangenerate a fallback message that causes the UE 102 to use the 4G corenetwork 132. In various examples, the UE 102 and/or the UE 106 can beassociated with a pre-paid account such as a mobile virtual networkoperator (MVNO).

Though the TAS 114, the IMS 110, and the OCS 122 are illustrated in FIG.4 individually, it is understood that the TAS 114, the IMS 110, and/orthe OCS 122 (of functionality provided therefrom) may be directlycoupled to and/or integrated into the IMS 110 or other sub-system of the5G system 104. Further, in some examples functionality provided by theIMS 110 and/or the TAS 114 may be implemented as a system separate toprovide services to other network architectures and/or other networkoperators.

In some examples, a messaging flow as shown in FIG. 4 can representactivity to determine charges by the TAS 114 during the establishing andmaintaining of a communication (e.g., the message 112 and/or thefallback message 134) between the UE 102 and the UE 106 in which the UE102 comprises a pre-paid account. For example, the UE 102 can send anINVITE(NR) message to the IMS 110 to initiate a call to the UE 106. TheIMS 110 can forward the INVITE(NR) message to the TAS 114. Uponreceiving the INVITE(NR) message, the TAS 114 can send a credit controlrequest (CCR) and a credit control answer (CCA) initial message to theOCS 122. In such examples, the OCS 122 can send information related tothe CCR/CCA message to the TAS 114 indicating credit related to thepre-paid account of the UE 102 (e.g., an amount of available credit,past consumption, as the like). For instance, the OCS 122 can provide anindication of whether the UE 102 has sufficient credit to initiate aVoNR call via the 5G core network 108.

In some examples, the UE 102 can send a PRACK(NR) message to the IMS 110which can forward the PRACK(NR) to the TAS 114. As illustrated in FIG. 4, the UE 102 can undergo EPSFB (e.g., EPSFB 128) and send anacknowledgement ACK(LTE) to the IMS 110 which can forward the ACK(LTE)to the TAS 114 to indicate a change of network. In various example, themessage sent to the TAS 114 can include an identifier indicating atechnology type of the network, such as a PANI associated with the 5Gnetwork and a PANI associated with the LTE network.

Upon receiving the ACK(LTE), the TAS 114 can send a CCR-CCA updatemessage to the OCS 122 based at least in part on the TAS 114 identifyinga change in type of technology (e.g., identifying a change in the PANIof the UE 102 indicating the EPSFB 128 to the 4G core network 132). Uponreceiving the CCR-CCA update message, the OCS 122 can identify a creditassociated with the 4G core network 132 and exchange information thereofwith the TAS 114. In this way, the TAS 114 can notify the UE 102 of thecredit, and in some examples, enable communication to the UE 106 overthe 4G core network 132, including instances when the UE 102 did nothave sufficient credit to place a VoNR communication. Accordingly, theTAS 114 can provide functionality to connect the UE 102 and the UE 106in examples that would otherwise be denied based at least in part on theUE 102 not having credit to place the VoNR communication.

In some examples, the UE 102 can communicate with the UE 106 over the 5Gnetwork and/or the 4G network, and the TAS 114 can initiate, access,generate, or otherwise determine data usable by a charging system (theOCS 122) that determines charge(s) for the UE 102 during thecommunication in real-time. After the call ends, the TAS 114 canexchange charge information (e.g., shown as a CCR/CCA terminate messagein FIG. 4 ) about the one or more charges to the OCS 122. The TAS 114and/or the OCS 122 can determine call detail records based at least inpart on logic that combines or aggregates the charges. In such examples,the TAS 114 can act as an originating TAS by receiving an invite fromthe UE 102.

FIG. 4 also depicts the TAS 114 acting as a terminating TAS (e.g.,facilitating termination of the UE 106 to another component or UE). Insome examples, a CCR/CCA initial message can be exchanged between theTAS 114 and the OCS 122 to establish credit associated with a calloriginating by the UE 106. Subsequently, the UE 106 can send a sessionprogress 183(NR) message to the UE 102 which causes the 183(NR) messageto be sent from the IMS 110 to the TAS 114. As illustrated in FIG. 4 ,the UE 106 can undergo EPSFB (e.g., EPSFB 128) and send an invite 200OKINV(LTE) to the UE 102 which causes the IMS 110 to forward the 200OKINV(LTE) to the TAS 114 to indicate a change of network (e.g., a changein PANI indicating that the UE 106 has joined an LTE network as a resultof the UE 106 experiencing fallback).

Upon receiving the 200OK INV(LTE), the TAS 114 can send a CCR-CCA updatemessage to the OCS 122 to initiate and identify a credit associated withthe 4G core network 132 for the UE 106. The OCS 122 can exchange creditinformation with the TAS 114 and/or determine charges for the UE 106and/or the UE 102 associated with voice, video, text, and other types ofcommunication. In various examples, the OCS 122 can determine whethersufficient credit of a pre-paid account exists for communication betweenthe UE 102 and the UE 106 regardless of the type of communication (e.g.,online, offline, voice, video, and the like). In some examples, the OCS122 can indicate an amount of credit (minutes or other time period) tothe TAS 114 allowable for a given communication session and communicatean indication to the TAS 114 when the minutes are consumed. In exampleswhen the OCS 122 determines that the UE 102 and/or the UE 106 does nothave sufficient credit for a communication session (based on ratinglogic for the communication session), the OCS 122 can provide anindication of additional credit to enable a communication session tocontinue (such as when the credit becomes insufficient during thecommunication). In such examples, the additional credit provided by theOCS 122 can be communicated with the TAS 114 at the end of thecommunication. In examples when a communication ends prior to consumingthe available credit, the OCS 122 can determine an amount of unusedcredit (e.g., unused minutes) to update future credit associated withthe user account.

After the call ends between the UE 106 and the UE 102, the TAS 114 canexchange charge information (e.g., shown as a CCR/CCA terminate messageof the terminating TAS in FIG. 4 ) about the one or more charges withthe OCS 122.

Although FIGS. 3 and 4 depict a single telephony application server(e.g., the TAS 114), multiple telephony application servers (or otherserver types) may be implemented to perform the techniques describedherein. For instance, the UE 102 may be associated with a firsttelephony application server and the UE 106 may be associated with asecond telephony application server different from the first telephonyapplication server. In such examples, the first telephony applicationserver and the second telephony application server can each generate oneor more CDRs for online and/or offline charging determinations forrespective users of each device. For example, the first telephonyapplication server serving or otherwise associated with the UE 102 canindicate originating service EPSFB while the second telephonyapplication server serving the UE 106 can indicate terminating serviceEPSFB. In this way, the first telephony application server can generateoriginating call detail record(s) associated with a user making a MobileOriginating (MO) communication and the second telephony applicationserver can generate terminating call detail record(s) associated withthe user making a Mobile Terminating (MT) communication.

FIG. 5 depicts a flowchart of an example process 500 for determiningcharges by an example server for an example user equipment. Some or allof the process 500 may be performed by one or more components in FIGS.1-4 and 7 , as described herein. For example, some or all of process 500may be performed by the IMS 110, the TAS 114, the IMC 120, the OCS 122,and/or the CG 126.

At operation 502, the process may include receiving, by a server of afifth generation telecommunications network, a message from a first userequipment (UE) indicating a request for communication with a second UE.In some examples, the operation 502 may include the TAS 114 receiving amessage from the UE 102 comprising a request for a VoNR communication, aViNR communication, or other service provided by the 5G system 104. Byway of example and not limitation, a UE of a fifth generation systemthat includes a fifth generation core network can send a messagecomprising text, an image, a video, and/or a file transfer to the IMS110 (or other system) and/or the TAS 114 requesting a communicationsession with one or more additional UEs.

In some examples, the message from the UE 102 can comprise an identifierthat indicates information about a type of technology (e.g., a 5G corenetwork 108) that the UE 102 is using to communicate the message (e.g.,the message 112). For instance, the TAS 114 can receiveP-Access-Network-Information (PANI) indicating a carrier or a type oftechnology associated with a network, and/or receive a SIP User-Agentheader indicating a type of device, a device manufacture, and otherinformation pertaining to an origination UE and/or network. In someexamples, the UE 102 can be associated with a specific carrier, a MVNO,or a pre-paid account.

At operation 504, the process may include determining, by the server andbased at least in part on an identifier of the first UE indicating atype of technology associated with the message, that the communicationcomprises Evolved Packet System Fallback (EPSFB) from the fifthgeneration telecommunications network to a second network different fromthe fifth generation telecommunications network. For instance, the IMS110 and/or the TAS 114 can determine that the 5G core network 108 isunable to complete the request for the communication (e.g., a VoNRcommunication) to the second UE using the 5G core network and thereforerequires the second network (e.g., a 4G network, a 3G network, and thelike) to complete the communication request. In various examples, theTAS 114 can determine that an identifier (e.g., a first PANI) associatedwith the fifth generation telecommunications network is different forman identifier (e.g., a second PANI) associated with the second network.The TAS 114 can also determine that fallback (EPSFB) occurred based atleast in part on the difference between the first PANI and the secondPANI. In some examples, the EPSFB occurs at the initiation of a callbetween the UE 102 and the UE 106 while in other examples, the messageform the UE 102 can be received after a portion of a VoNR communication(or other communication) has already been completed using the 5G corenetwork.

In some examples, the TAS 114 can access, receive, or otherwisedetermine an identifier associated with the UE 102 (and/or the UE 106)from a memory, a database, or other storage device that indicates a typeof technology associated with the second network (e.g., 4G, 3G, and soon). For instance, the TAS 114 can access the identifier from themessage received from the UE 102 requesting a communication with the UE106.

In examples when a communication between the UE 102 and the UE 106occurs over the 5G core network 108 prior to the UE 102 falling back tothe second network, the TAS 114 can access (e.g., from a previousmessage, a memory, a database, and the like) a first identifierassociated with the UE 102 indicating the communication to the 5G corenetwork 108. In such examples, the TAS 114 can access or otherwisereceive, from the same message or another message of the UE 102, asecond identifier and determine, based at least in part on comparing thefirst and second identifiers, that a change of an identifier valueoccurred (e.g., a change from a first PANI value to a second PANIvalue). For instance, the TAS 114 can compare two PANI values anddetermine that the UE 102 has changed from a 5G core network to a 4Gcore network.

By accessing the identifier(s), the TAS 114 can cause charge(s) to bedetermined based at least in part on a type of technology used tocommunicate the message. In some instances, the identifier(s) can besaved in a database, server, or other memory resource for access at alater time. In some examples, the TAS 114 can determine changes in theidentifiers based at least in part on accessing such information therebyenabling charges to be configured in substantially real-time based onwhich network the UE uses to communicate.

At operation 506, the process may include sending, by the server,information indicating the EPSFB to a charging system. In some examples,the operation 506 may include the TAS 114 sending data representative ofthe EPSFB to a charging system such as the OCS 122 and/or the CG 126. Invarious examples, logic employed by the charging system can determineonline and/or offline charges associated with the message.

In some examples, the TAS 114 can determine account informationassociated with the UE (e.g., which carrier the UE 102 has an accountwith or whether the UE 102 is associated with a pre-paid account, and soon) based at least in part on communicating data with a Home SubscriberServer (HSS). For instance, the TAS 114 can receive or otherwisedetermine a user profile from the HSS indicating whether online and/oroffline charges are to be applied. In some examples, informationassociated with the user profile may be shared or communicated betweenthe TAS server 114 and the charging system. The TAS server 114 can, insome examples, download the user profile associated with the UE 102and/or the UE 106 responsive to registration with the IMS 110 and/orresponsive to providing unregistered service to the UE 102 and/or the UE106 while communication is established.

At operation 508, the process may include receiving, by the server, acharge for the first UE associated with the communication to the secondUE over the second network based at least in part on the informationindicating the EPSFB sent to the charging system. In some examples, theoperation 508 may include the TAS 114 receiving data indicating one ormore charges for the UE 102 and/or the UE 106 to communicate with thesecond UE (e.g., the other of the UE 102 or the UE 106) over the 4G corenetwork. In various examples, the charge(s) can comprise an onlinecharge, and offline charge, or other charge associated with thecommunication. In some examples, the charge can be determined by thecharge system during initiation of the communication while in otherexamples the charge can be determined in real-time during thecommunication. Further, the charge system can, in some examples,identify or generate charges during the communication for each portioncompleted on the 5G network and the 4G network. For example, the TAS 114can provide an indication of EPSFB in a call detail record or other datasent to the charge system to enable the charge system to determine arate for the UE 102 corresponding to each technology used when the UE102 is associated with an MVNO.

FIG. 6 depicts a flowchart of an example process 600 for determiningcharges by an example server for an example user equipment. Some or allof the process 600 may be performed by one or more components in FIGS.1-4 and 7 , as described herein. For example, some or all of process 600may be performed by the IMS 110, the TAS 114, the IMC 120, the OCS 122,and/or the CG 126.

At operation 602, the process may include establishing a first portionof a communication over a first network at a first time. In someexamples, the operation 602 may include a communication between two ormore UEs over a 5G network, a 4G network, a 3G network, or the like. Anidentifier (e.g., a PANI) associated with one or more of the UEs in thecommunication can be sent by the first network to the TAS 114. Invarious examples, the first portion of the communication can representpart of a call taking place or completed on the first network. In someexamples, the communication can be established based at least in part onreceiving a message from a UE (e.g., the UE 102) comprising a requestfor a VoNR communication, a ViNR communication, or other serviceprovided by the first network. In some examples, a UE associated withthe communication can include a MVNO or a pre-paid account.

At operation 604, the process may include establishing a second portionof the communication over a second network at a second time differentfrom the first time. In some examples, the operation 604 may include adifferent network from the first network establishing another portion ofthe communication, such as a portion of a call. For instance, thecommunication may start as the first portion on a 5G network and switchto a 4G network as part of a fallback operation (e.g., EPSFB) during thesecond portion (or vice versa). An identifier (e.g., a PANI) associatedwith one or more of the UEs in the communication can be sent by thesecond network to the TAS 114 to indicate a type of network used duringthe second portion of the communication. In various examples, the secondportion of the communication can represent part of a call taking placeor completed on the second network. In some examples, the communicationcan be established on the second network to maintain voice, text, and/orvideo communications initiated on the first network.

At operation 606, the process may include accessing, by a server, anidentifier of a user equipment (UE) associated with the communication,the identifier indicating a type of technology of the first network atthe first time. In some examples, the operation 606 may include the TAS114 receiving or accessing the identifier associated with the UE 102that indicates a type of technology associated with the first network(e.g., 5G, 4G, 3G, and so on) from a message of the communication, amemory, or a database associated with the TAS 114. The TAS 114 canaccess the identifier, for example, from the message received from theUE 102. In some examples, the identifier can indicate information abouta type of technology (e.g., a 5G core network 108, a 4G core network132, and so on) used for the communication over the first network. Forinstance, the TAS 114 can receive P-Access-Network-Information (PANI)indicating a carrier or a type of technology associated with a network,and/or receive a SIP User-Agent header indicating a type of device, adevice manufacture, and other information pertaining to an originationUE and/or network

At operation 608, the process may include determining, by the server, achange in the identifier associated with the UE. In examples when acommunication between the UE 102 and the UE 106 occurs over the firstnetwork (e.g., the 5G core network 108) and the UE 102 falls back to thesecond network, the TAS 114 can access (e.g., from memory, a database, amessage, and the like) a second identifier associated with the UE 102indicating the communication from the 5G core network 108 to the secondnetwork. In such examples, the TAS 114 can access or otherwise receive,from another message of the UE 102, memory, and so on, the secondidentifier and determine, based at least in part on comparing the firstand second identifiers, that a change of an identifier value occurred(e.g., a difference between a first PANI value and a second PANI value).For instance, the TAS 114 can compare two PANI values and determine thatthe UE 102 has changed from a 5G core network to a 4G core network (orvice versa). In some examples, the TAS 114 can indicate an account typeassociated with the UE (e.g., which carrier the UE 102 has an accountwith, or whether the UE 102 is associated with a pre-paid account, justto name a few). For instance, the TAS 114 can receive or otherwisedetermine a user profile from the HSS indicating whether online and/oroffline charges are to be applied. In some examples, informationassociated with the user profile may be shared or communicated betweenthe TAS server 114 and the charging system (e.g., the OCS 122 and/or theCG 126).

At operation 610, the process may include determining, by the server, afirst charge for the UE associated with the communication over the firstnetwork and a second charge for the UE associated with the communicationover the second network. In some examples, the operation 608 may includethe IMS 110 and/or the TAS 114 receiving determinations of charges fromthe charging system for the UE 102 to communicate with the second UEover the 5G core network 108 and the 4G core network 132. In variousexamples, the first charge and/or the second charge can comprise anonline charge, and offline charge, or other charge associated with thecommunication. In some examples, the first charge and/or the secondcharge can be determined by the charging system during the communicationover the first network and the second network in substantiallyreal-time, and communicated to the TAS 114. In this way, the TAS 114can, in some examples, identify and send an indication of EPSFB (basedon a change in the PANI) to a charging system for generating charges orrates during the communication for the first portion on the firstnetwork and the second portion on the 4G network. In some examples,information such as a call detail record, an indication of EPSFB, userprofile, or other information determined by the TAS 114, can be used todetermine a specific UE type which performs EPSFB more often relative toother US types. In some examples, the information associated with orstored by the TAS 114 can be sent to a server, computing device, machinelearned model, and the like, to improve design of the 5G core networkrelative to new radio services such as VoNR, ViNR, RCS services, and thelike.

In various examples, information about the call detail record, the firstcharge and/or the second charge can be sent from the TAS 114 to othercomponents of the first network or the second network that enablenetwork parameters to be determined that improve functioning of thefirst network and/or the second network (versus not sending theinformation). For example, the TAS sever 114 can share information withother components of other networks that is usable to avoid futurecommunications from experiencing fallback (e.g., EPSFB 128). In someexamples, the network parameters can be determine by a machine learnedmodel to provide peak throughput, and can include one or more of: abandwidth, a Time Division Duplex (TDD) ratio configuration, afrequency, a transmission power, or a beamforming Precoding MatrixIndicator (PMI), a location, a signal strength, or a signal-to-noiseratio, just to name a few. In various examples, the network parametersare usable to transmit data between the one or more UEs, includingimproving design and operation of VoNR communications over the networkwith optimal efficiency and accuracy. For instance, a computing device(or human operator thereof) can analyze the instances of fallback toidentify a location, a base station, a design parameter, or other causeof the fallback to reduce as amount of fallback that occurs in thefuture. In various examples, the techniques described herein can be usedto implement changes in the way a network is designed, such as when newservices are being deployed. In this way, locations, base stations (orother network elements), and other design parameters can be adjusted,modified, or added to increase an amount of devices that can utilize thenew services.

FIG. 7 depicts an example system architecture for a UE 102, inaccordance with various examples. As shown, a UE 102 can have memory 702storing a call setup manager 704, and other modules and data 706. A UE102 can also comprise processor(s) 708, radio interfaces 710, a display712, output devices 714, input devices 716, and/or a machine readablemedium 718.

In various examples, the memory 702 can include system memory, which maybe volatile (such as RAM), non-volatile (such as ROM, flash memory,etc.) or some combination of the two. The memory 702 can further includenon-transitory computer-readable media, such as volatile andnonvolatile, removable and non-removable media implemented in any methodor technology for storage of information, such as computer readableinstructions, data structures, program modules, or other data. Systemmemory, removable storage, and non-removable storage are all examples ofnon-transitory computer-readable media. Examples of non-transitorycomputer-readable media include, but are not limited to, RAM, ROM,EEPROM, flash memory or other memory technology, CD-ROM, digitalversatile discs (DVD) or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other non-transitory medium which can be used to store desiredinformation and which can be accessed by the UE 102. Any suchnon-transitory computer-readable media may be part of the UE 102.

The call setup manager 704 can send and/or receive messages comprising aVoNR service, a ViNR service, and/or an RCS service including SIPmessages associated with setup and management of a call session via theIMS. The SIP messages can include any of the SIP messages shown in FIG.5 , and/or other SIP messages.

The other modules and data 706 can be utilized by the UE 102 to performor enable performing any action taken by the UE 102. The modules anddata 706 can include a UE platform, operating system, and applications,and data utilized by the platform, operating system, and applications.

In various examples, the processor(s) 708 can be a central processingunit (CPU), a graphics processing unit (GPU), or both CPU and GPU, orany other type of processing unit. Each of the one or more processor(s)708 may have numerous arithmetic logic units (ALUs) that performarithmetic and logical operations, as well as one or more control units(CUs) that extract instructions and stored content from processor cachememory, and then executes these instructions by calling on the ALUs, asnecessary, during program execution. The processor(s) 708 may also beresponsible for executing all computer applications stored in the memory702, which can be associated with common types of volatile (RAM) and/ornonvolatile (ROM) memory.

The radio interfaces 710 can include transceivers, modems, interfaces,antennas, and/or other components that perform or assist in exchangingradio frequency (RF) communications with base stations of thetelecommunication network, a Wi-Fi access point, and/or otherwiseimplement connections with one or more networks. For example, the radiointerfaces 710 can be compatible with multiple radio accesstechnologies, such as 5G radio access technologies and 4G/LTE radioaccess technologies. Accordingly, the radio interfaces 710 can allow theUE 102 to connect to the 5G system 104 described herein.

The display 712 can be a liquid crystal display or any other type ofdisplay commonly used in UEs. For example, display 712 may be atouch-sensitive display screen, and can then also act as an input deviceor keypad, such as for providing a soft-key keyboard, navigationbuttons, or any other type of input. The output devices 714 can includeany sort of output devices known in the art, such as the display 712,speakers, a vibrating mechanism, and/or a tactile feedback mechanism.Output devices 714 can also include ports for one or more peripheraldevices, such as headphones, peripheral speakers, and/or a peripheraldisplay. The input devices 716 can include any sort of input devicesknown in the art. For example, input devices 716 can include amicrophone, a keyboard/keypad, and/or a touch-sensitive display, such asthe touch-sensitive display screen described above. A keyboard/keypadcan be a push button numeric dialing pad, a multi-key keyboard, or oneor more other types of keys or buttons, and can also include ajoystick-like controller, designated navigation buttons, or any othertype of input mechanism.

The machine readable medium 718 can store one or more sets ofinstructions, such as software or firmware, that embodies any one ormore of the methodologies or functions described herein. Theinstructions can also reside, completely or at least partially, withinthe memory 702, processor(s) 708, and/or radio interface(s) 710 duringexecution thereof by the UE 102. The memory 702 and the processor(s) 708also can constitute machine readable media 718.

The various techniques described herein may be implemented in thecontext of computer-executable instructions or software, such as programmodules, that are stored in computer-readable storage and executed bythe processor(s) of one or more computing devices such as thoseillustrated in the figures. Generally, program modules include routines,programs, objects, components, data structures, etc., and defineoperating logic for performing particular tasks or implement particularabstract data types.

Other architectures may be used to implement the described functionalityand are intended to be within the scope of this disclosure. Furthermore,although specific distributions of responsibilities are defined abovefor purposes of discussion, the various functions and responsibilitiesmight be distributed and divided in different ways, depending oncircumstances.

Similarly, software may be stored and distributed in various ways andusing different means, and the particular software storage and executionconfigurations described above may be varied in many different ways.Thus, software implementing the techniques described above may bedistributed on various types of computer-readable media, not limited tothe forms of memory that are specifically described.

CONCLUSION

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter is not necessarily limited to the specificfeatures or acts described above. Rather, the specific features and actsdescribed above are disclosed as example embodiments.

While one or more examples of the techniques described herein have beendescribed, various alterations, additions, permutations and equivalentsthereof are included within the scope of the techniques describedherein. For instance, techniques described in FIGS. 5 and 6 can becombined in various ways.

In the description of examples, reference is made to the accompanyingdrawings that form a part hereof, which show by way of illustrationspecific examples of the claimed subject matter. It is to be understoodthat other examples can be used and that changes or alterations, such asstructural changes, can be made. Such examples, changes or alterationsare not necessarily departures from the scope with respect to theintended claimed subject matter. While the steps herein can be presentedin a certain order, in some cases the ordering can be changed so thatcertain inputs are provided at different times or in a different orderwithout changing the function of the systems and methods described. Thedisclosed procedures could also be executed in different orders.Additionally, various computations that are herein need not be performedin the order disclosed, and other examples using alternative orderingsof the computations could be readily implemented. In addition to beingreordered, the computations could also be decomposed intosub-computations with the same results.

What is claimed is:
 1. A method comprising: establishing a first portion of a communication over a first network at a first time; establishing a second portion of the communication over a second network at a second time different from the first time; accessing, by a server, an identifier of a user equipment (UE) associated with the communication, the identifier indicating a type of technology of the first network at the first time; determining, by the server, a change in the identifier associated with the UE; and determining, by the server, a first charge for the UE associated with the communication over the first network and a second charge for the UE associated with the communication over the second network.
 2. The method of claim 1, further comprising: combining, the first charge and the second charge; and determining at least one of a call detail record, an online charge, or an offline charge for the UE based at least in part on the combining.
 3. The method of claim 1, wherein determining the change in the identifier comprises: identifying, by the server, first P-Access-Network-Information associated with the first network; identifying, by the server, second P-Access-Network-Information associated with the second network; and determining a difference between the first P-Access-Network-Information and the second P-Access-Network-Information.
 4. The method of claim 1, wherein: establishing the second portion of the communication over the second network at the second time is caused by Evolved Packet System Fallback (EPSFB) from the first network to the second network.
 5. The method of claim 1, wherein: the first network comprises a fifth generation telecommunications network; the second network comprises a fourth generation telecommunications network; and the communication is associated with a Voice over New Radio (VoNR) communication or Video over New Radio (ViNR).
 6. The method of claim 1, wherein: the server comprises a Telephony Application Server (TAS) associated with an Internet Protocol (IP) Multimedia Subsystem (IMS); and the TAS comprises one or more of: charge detail records interface, an online charging (Ro) interface, or an offline charging (Rf) interface.
 7. The method of claim 1, further comprising: determining, by the server and based at least in part on the identifier associated with the UE indicating a type of technology associated with a message received by the server, that a communication request associated with the message comprises Evolved Packet System Fallback (EPSFB) from the first network to the second network; sending, by the server, information indicating the EPSFB to a charging system; and receiving, by the server, a charge for the UE associated with a communication to another UE over the second network based at least in part on the information indicating the EPSFB sent to the charging system.
 8. A system comprising: one or more processors; and memory storing computer-executable instructions that, when executed by the one or more processors, cause the system to perform operations comprising: establishing a first portion of a communication over a first network at a first time; establishing a second portion of the communication over a second network at a second time different from the first time; accessing, by a server, an identifier of a user equipment (UE) associated with the communication, the identifier indicating a type of technology of the first network at the first time; determining, by the server, a change in the identifier associated with the UE; and determining, by the server, a first charge for the UE associated with the communication over the first network and a second charge for the UE associated with the communication over the second network.
 9. The system of claim 8, further comprising: combining, the first charge and the second charge; and determining at least one of a call detail record, an online charge, or an offline charge for the UE based at least in part on the combining.
 10. The system of claim 8, wherein determining the change in the identifier comprises: identifying, by the server, first P-Access-Network-Information associated with the first network; identifying, by the server, second P-Access-Network-Information associated with the second network; and determining a difference between the first P-Access-Network-Information and the second P-Access-Network-Information.
 11. The system of claim 8, wherein: establishing the second portion of the communication over the second network at the second time is caused by Evolved Packet System Fallback (EPSFB) from the first network to the second network.
 12. The system of claim 8, wherein: the first network comprises a fifth generation telecommunications network; the second network comprises a fourth generation telecommunications network; and the communication is associated with a Voice over New Radio (VoNR) communication or Video over New Radio (ViNR).
 13. The system of claim 8, wherein: the server comprises a Telephony Application Server (TAS) associated with an Internet Protocol (IP) Multimedia Subsystem (IMS); and the TAS comprises one or more of: charge detail records interface, an online charging (Ro) interface, or an offline charging (Rf) interface.
 14. The system of claim 8, the operations further comprising: determining, by the server and based at least in part on the identifier associated with the UE indicating a type of technology associated with a message received by the server, that a communication request associated with the message comprises Evolved Packet System Fallback (EPSFB) from the first network to the second network; sending, by the server, information indicating the EPSFB to a charging system; and receiving, by the server, a charge for the UE associated with a communication to another UE over the second network based at least in part on the information indicating the EPSFB sent to the charging system.
 15. A computing device comprising: one or more processors; and memory storing computer-executable instructions that, when executed by the one or more processors, cause the computing device to perform operations comprising: establishing a first portion of a communication over a first network at a first time; establishing a second portion of the communication over a second network at a second time different from the first time; accessing, by the computing device, an identifier of a user equipment (UE) associated with the communication, the identifier indicating a type of technology of the first network at the first time; determining, by the computing device, a change in the identifier associated with the UE; and determining, by the computing device, a first charge for the UE associated with the communication over the first network and a second charge for the UE associated with the communication over the second network.
 16. The computing device of claim 15, further comprising: combining, the first charge and the second charge; and determining at least one of a call detail record, an online charge, or an offline charge for the UE based at least in part on the combining.
 17. The computing device of claim 15, wherein determining the change in the identifier comprises: identifying, by the computing device, first P-Access-Network-Information associated with the first network; identifying, by the computing device, second P-Access-Network-Information associated with the second network; and determining a difference between the first P-Access-Network-Information and the second P-Access-Network-Information.
 18. The computing device of claim 15, wherein: establishing the second portion of the communication over the second network at the second time is caused by Evolved Packet System Fallback (EPSFB) from the first network to the second network.
 19. The computing device of claim 15, wherein: the first network comprises a fifth generation telecommunications network; the second network comprises a fourth generation telecommunications network; and the communication is associated with a Voice over New Radio (VoNR) communication or Video over New Radio (ViNR).
 20. The computing device of claim 15, wherein: the computing device comprises a Telephony Application Server (TAS) associated with an Internet Protocol (IP) Multimedia Subsystem (IMS); and the TAS comprises one or more of: charge detail records interface, an online charging (Ro) interface, or an offline charging (Rf) interface. 